This invention relates to coating compositions and compositions to be used as additives. More specifically, this invention relates to siloxy-polymer containing compositions in a solvent, wherein the composition does not sting on application to the skin of a user.
Coating compositions are desired in the art, both as skin protecting compositions and medicament containing compositions.
U.S. Pat. Nos. 5,103,812 and 4,987,893 relate to a conformable bandage and coating materials. These materials are combinations of alkylsiloxy silicone containing polymers admixed with liquid polydimethylsiloxanes. Polymers of these compositions are incorporated into a solvent system that is preferably polydimethylsiloxane having the solubility parameter of 6.8-7.2 [cal/cm3]xc2xd. See column 5, lines 50-55. These polymer films are also said to be able to be cast from liquids containing good solvents with solubility parameters of between about 9 to 10 [cal/cm3]xc2xd. Specific examples of such solvents are tetrahydrofuran and ethylacetate. See column 6, lines 50-54.
A composition for application to the skin, comprising: 1-40% siloxane containing polymer; 60-99% of an Alkane-Based Siloxy Polymer Reaction Solvent, and 0-15% of adjuvants is provided.
A method of making a siloxane-containing polymer is also provided comprising vinyl containing alkylsiloxysilanes alone or as co-, ter- or multi component polymers including other polymerizable monomers, which method comprises undertaking the polymerization in an alkane solvent selected from the group consisting of C5xe2x80x94Oxe2x80x945xe2x80x94C9 straight, branched or cyclic alkanes so that the reaction provides a composition having a polymer content greater than 15% by weight.
Aqueous gel compositions are also provided.
No-sting skin protectants are described in U.S. Pat. Nos. 5,103,812 and 4,987,893, but these materials cannot be provided at higher solids than 15% without becoming very stringy and pituitous. At higher solids content, the polymer will not spread when painted onto the skin from the described formulation. Furthermore, the method for applying thick coatings to the skin as described in the prior art is through multiple applications of thin coatings. In the prior art method, towelette wipes having solutions comprising 10% polymer content are applied over areas to be treated and dried. By the time the coating is dry on the skin, the applicator wipe may be also dry and a new wipe must be used.
Surprisingly, it has been found that non-stinging coating compositions may be provided utilizing a siloxy polymer, but which is cast from a solvent not previously thought to be appropriate for such use. Optionally, the polymer content of the inventive compositions may be significantly higher than the polymer content possible in prior art compositions, while maintaining good handleability properties.
More specifically, the solvent system for the compositions of the present invention is selected such that it is an Alkane-Based Siloxy Polymer Reaction Solvent. An Alkane-Based Siloxy Polymer Reaction Solvent is a solvent system that primarily contains straight, branched or cyclic alkanes, and is capable of acting as the reaction solvent (i.e. the non-reactive fluid portion of a reaction composition) for the polymerization reaction of the specific monomer composition of TRIS/Methyl Methacrylate/2-Ethylhexyl acrylate in a 53/39/8 weight ratio. The solvent system is readily identified in a routine evaluation by undertaking a polymerization reaction using the specific monomer composition described above under a Standard Polymerization Reaction as defined below.
A Standard Polymerization Reaction comprises reacting 20% total monomer concentration by weight based on monomer plus solvent with VAZO 67 free radical initiator used at 0.3% by weight based on total monomer at a reaction temperature of 70xc2x0 C. under nitrogen for 36 hours (or less time if greater than 90% monomer conversion has occurred). A solvent system is deemed to be an Alkane-Based Siloxy Polymer Reaction Solvent if, after cooling to room temperature, the reacted composition yields a clear, pourable solution of polymer, and the inherent viscosity (xe2x80x9cIVxe2x80x9d as tested by ASTM D2857-95 at 25xc2x0 C. and according to principles discussed in Experiments in Polymer Science, by Edward A. Collins, Jan Bares and Fred W. Billmeyer, New York, Wiley (1973) pp 146-153.) of the polymer product is measured in ethyl acetate solvent at a nominal solids concentration of 0.5% (w/v)is less than 0.5 dl/g. Solvents which yield polymer with inherent viscosity greater than 0.5 dl/g are unsuitable.
A specific procedure for the test is detailed below.
A mixture of 4.24 g TRIS, 3.12g methyl methacrylate and 0.64g 2-ethyl hexyl acrylate is dissolved in 32 g of solvent in a 4 oz narrow mouth flint glass bottle and 0.024 g of VAZO 67 is added. The solution is purged with nitrogen at a flow rate of 1 liter/ minute for two minutes to remove dissolved oxygen. The bottle is closed tightly with a teflon lined metal cap and placed in a launder-o-meter preset at 70xc2x0 C. for at least 24 hours. Conversion is determined from measurement of percent non volatile solids by loss on drying at 105xc2x0 C. for 60 minutes.
Preferred solvents of the present invention are selected from one or more C5-C12 straight, branched, or cyclic alkanes. Particularly preferred solvents are methylcyclopentane; n-heptane; n-octane; n-nonane; 2,2,4-trimethyl pentane; 3,4-dimethyl hexane. The solvent system may also comprise a blend of solvents that are a mixture of straight, branched or cyclic C10-C12 alkanes with one or more C5-C9 straight, branched or cyclic alkanes.
For example, preferred solvent blends include mixtures of one or more of n-decane, n-undecane or n-dodecane with one or more of methylcyclopentane; n-heptane; n-octane; n-nonane; 2,2,4-trimethyl pentane; 3,4-dimethyl hexane.
The present inventive compositions are preferably provided as a skin protecting conformable bandage that is painted on. Alternatively, the compositions of the present invention may be provided as a component in a cosmetic or medicament containing composition.
The liquid polymer-containing coating materials of this invention comprise a siloxane containing polymer and a solvent system which is non-stinging to a user. Preferably the polymer is present from 1 to 40% by weight and the solvent is present in amounts of 60 to 99%. The material forms a coating or bandage in the form of a dried film when applied to a surface or the skin of a user.
Advantageously, the present invention provides the ability to manufacture the polymer in the same solvent as used in the final formulation. It has been found that it is exceedingly difficult to manufacture this polymer in the prior art solvent system hexamethyl disiloxane (xe2x80x9cHMDSxe2x80x9d). The ability to manufacture in the same solvent as the ultimate product is a significant advantage in cost savings, and additionally provides a more complete distribution of reaction products that may aid in film formation.
Use of the solvent system of the present invention allows for incorporation of higher solids content of the polymer, and also allows for selection of the polymer formulation to provide suitable materials for the desired use at lower siloxy silane component content.
It has surprisingly been found that the alkane solvents as described herein may be highly effective cosolvents with volatile siloxane (such as HMDS), which can substantially increase the amount of solids content that may be obtained without becoming pituitous. Additionally, it has been found that the addition of about 5%-10% of Tea Tree Oil (oil of Melaleuca alternifolia) and the like similarly increases the amount of solids content that may be obtained without becoming pituitous.
Preferably, the siloxane containing polymer comprises at least one vinyl containing alkylsiloxysilane and an addition polymerizable comonomer.
It is a feature of the invention that the liquid materials can act at room temperature (20xc2x0 C.) when applied to skin, nails, or mucous membranes of a user to form films in minutes or less, which films are excellent bandages. The films are conformable, comfortable and can be elastic and flexible. The films do not irritate the skin and mucous membrane when sprayed or deposited in any way during application and in use after drying. The bandages are substantially painless and can be easily removed substantially without pain. The dried bandages formed are substantially non-water sensitive, and waterproof and have high water vapor and oxygen gas transmission therethrough. The bandages form when applied over surfaces wet with water, blood or body fluids, in short times at standard room temperature and reasonable variants thereof. The liquid composition and/or dried polymer film can have various medicaments or other agents incorporated therein for maintaining sterility and/or for release to the underlying area of the body of a user. For example, perfumes, antimicrobial, botanicals, medicants, or similar materials can be released from the coatings.
The siloxane containing polymers of this invention can comprise vinyl containing alkylsiloxysilanes alone or as co-, ter- or multi-component polymers which can include other polymerizable monomers that do not make the polymers hydrophilic.
Typical vinylaklylsiloxysilanes that may be utilized are:
3-methacryloyloxypropyltris(trimethylsiloxy)silane (TRIS);
3-methacryloyloxypropylpentamethyldisiloxane;
3-methacryloyloxypropylbis(trimethylsiloxy)methylsilane;
3-acryloyloxypropylmethylbis(trimethylsiloxy)silane;
3-acryloyloxypropyltris(trimethylsiloxy)silane; and others.
Typical addition polymerizable monomers which may be reacted with the vinylalkylsiloxysilanes to form multi component polymers are: methyl methacrylate methyl acrylate, tetrahydrofurfuryl methacrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, n-lauryl acrylate, n-lauryl methacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, isodecyl acrylate, isodecyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isobornyl acrylate, isobornyl methacrylate, benzyl methacrylate, 2-butoxyethyl acrylate, n-butyl acrylate, n-butyl methacrylate, ethyl acrylate, ethyl methacrylate, dimethyl itaconate, di-n butyl itaconate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, furfuryl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, isobutyl acrylate, isobutyl methacrylate, isopropyl methacrylate, methyl acrylate, alpha methyl styrene, styrene, p-t-butyl styrene, 4-methoxystyrene, n-octadecyl acrylate, n-otadecyl methacrylate, 2-phenylethyl methacrylate, n-tridecyl methacrylate, vinyl benzoate, vinyl naphthalene. In addition, fluorinated siloxanes, fluorinated itaconates, fluorinated methacrylates or acrylates, such as hexafluoroisopropyl methacrylate, can be used.
Any hydrophobic polymerizable monomer can be used as long as the resulting copolymer has desired O2 and H2O vapor permeability. These additional polymerizable comonomers can be present in amounts up to 0.85 mole fraction.
The polymers of the invention are preferably in proportions between about 15-100 mole % vinylalkylsiloxysilane which component maintains the desired compatibility of the polymer in the volatile liquid polydimethylsiloxanes with polar adjuvants, provides high moisture and oxygen permeability, and provides biocompatibility. A range of 20 to 40 mole % of the vinylalkylsiloxysilane in the polymer is preferred in the polymer of this invention. Other addition polymerizable monomers may be copolymerized with the vinylalkylsiloxysilanes between about 0-85% mole of the polymer composition to adjust permeability, adhesion, toughness, elasticity, temperature stability, and impact resistance, among other film qualities.
The polymers may be linear, branched, or slightly cross-linked and can be homo, co-, ter- or multi polymers. They may be random copolymers or segmental in nature.
Typical vinylalkylsiloxysilane monomers can have the following formulas:
CH2xe2x95x90C(R1)COOR2SiR3R4R5
Where
R1=H,
CH3, or
CH2COORxe2x80x2,
Where R2=alkyl (C1-C4) or CH2CH(OH)CH2,
Where R3, R4, R5=OSi(Y)3, or alkyl (C1-C6),
Wherein, at least one of R3, R4, R5=OSi(Y)3 
Where
Y=alkyl (C1-C6), OSi(Z)3 or
R2OOC(R1)Cxe2x95x90CH2,
Where Z=alkyl (C1-C6), aryl, and
Where Rxe2x80x2=R2SiR3R4R5 
The polymers may have molecular weights from 50,000 to several million. The preferred molecular weight range is 50,000 to 500,000 weight average molecular weight. Lower molecular weight polymers have notably higher solubility in the solvents and solvent systems of this invention and hence, while they can be film formers, they generally are slow to dry and remain tacky. The molecular weight of the polymers may be controlled by varying initiator, initiator concentration, reaction temperature, reaction solvent, and/or reaction method.
Most preferably, the polymers of the invention are acrylate or methacrylate terpolymers having an A monomer component that is a silane derivative, a B monomer component that when provided as a homopolymer would prepare a xe2x80x9chardxe2x80x9d polymer, and a C monomer component that, when provided as a homopolymer would prepare a xe2x80x9csoftxe2x80x9d polymer.
For the A monomer, examples of the silane derivatives are as described above. B monomers are xe2x80x9chardxe2x80x9d where the corresponding homopolymer typically has a glass transition temperature (Tg) of more than about xe2x88x925xc2x0 C. Examples of such monomers are acrylate or methacrylate monomers, preferably C1-C4 alkyl methacrylates. Most preferably, the hard monomer is methyl methacrylate.
Other examples of monomers that can be used for the hard monomer component are monomers having the requisite Tg values including methacrylates having a structure other than delineated above, such as benzyl methacrylate and isobornyl methacrylate methcrylamide such as N t butylmethacrylamide; acrylates such as isobornyl acrylate; acrylamides such as N butylacrylamide and N-t butylacrylamide; diesters of unsaturated dicarboxylic acids such as diethyl itaconate and diethyl fumarate; vinyl nitrites such acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; and monomers containing an aromatic ring such as styrene; xcex1-methyl styrene and vinyl toluene. xe2x80x98Cxe2x80x99 monomers may be selected from monomers that form soft homopolymers. xe2x80x9cSoftxe2x80x9d monomers are monomers where the corresponding homopolymer typically has a Tg of less than about 10xc2x0 C., provided that the hard monomer has a higher Tg than the soft monomer in each polymer. Such monomers are C4-C12 alkyl acrylates and C6-C12 alkyl methacrylates, wherein the alkyl groups are straight, branched, or cyclic. Most preferably, the soft monomer is selected from C7-C10 straight chain alkyl acrylates.
Other examples of monomers that can be used for the soft monomer component are monomers having the requisite Tg values including dienes, such as butadiene and isoprene; acrylamides, such as N-octylacrylamide; vinyl ethers such as butoxyethylene, propyloxyethylene and octyl oxyethylene; vinyl halides, such as 1,1-dichloroethylene; and vinyl esters such as vinyl caprate and vinyl laurate.
It has been found that this mix of monomers provide particularly advantageous abilities to adjust mole fraction ratios to optimize oxygen permeability, ductility, moisture vapor transmissibility of the film and cost of materials. Highly durable coatings are particularly desired to enable the coating to remain on the skin for an extended time and to provide superior protection.
Most preferably, the siloxane-containing polymer comprises about 50 to 60 weight percent A monomer, 25-45 weight percent B monomer, and about 3 to 20 weight percent of C monomer. A specifically preferred embodiment is where the siloxane-containing polymer comprises about 50 to 60 weight percent of 3-methacryloxypropyl tris(trimethylsiloxy)silane, about 25 to 45 weight percent methyl methacrylate, and about 3 to 20 weight percent of a monomer selected from C7-C10 straight chain or branched alkyl acylates.
Particularly preferred siloxane-containing polymers have an overall effective Tg of 20-80%, more preferably 40-70%, and most preferably 50-60xc2x0 C.
One variation in selection of monomers to be used in siloxane containing polymer is using more than one monomer within each category A, B, or C. For example, the polymer could comprise 57% 3-methacryloyloxypropyl tris(trimethylsiloxy)silane, 39% methyl methacrylate, 2% isooctyl acrylate and 2% decyl acrylate. The last two monomers each satisfy the definition of the C monomer, and together provide the desired quantity of this component.
Any free radical initiator can be used in forming the polymers including azobisisobutyronitrile; 2,2xe2x80x2-azobis(2,4 dimethylpentane nitrile); 2,2xe2x80x2-azobis-(2-methylbutane nitrile); potassium persulfate; ammonium persulfate; benzoyl peroxide; 2,5-dimethyl 2,5-bis(2-ethylhexanoylperoxy)hexane; and the like. The polymerization can be carried out by solution, emulsion, or suspension techniques.
Preferably, a polymer comprised of methyl methacrylate, isooctyl acrylate, and (xe2x80x9c3-methacryloxypropyl tris(trimethylsiloxy)silane) (xe2x80x9cTRISxe2x80x9d) is polymerized directly in a composition of 90% 2,2,4-trimethylpentane with 10% 3,4-dimethylhexane (Permethyl(copyright) 97A from Permethyl Specialties, LLC, Milmay, N.J.) or n-heptane at 25% nonvolatile finished polymer.
Adjuvants of the present compositions may comprise cosolvents, suspending aids, preservatives, antioxidants, active ingredients such as medicaments, humectants, emollients, slipagents, waxes, colorants (including dyes, pigments, colored particles, glitter and the like), flavorants, fragrances and the like. Adjuvants may also include solid materials, such as titanium dioxide and silica. Such materials may reduce tackiness of the overall composition, and additionally may perform a function such as acting as a sunscreen, handling modifier or to modify composition drying rates.
Preferred cosolvents that may be used as adjuvants of the present compositions include alcohols, ketones, oils and the like. Preferably, these cosolvents are present in an amount such that they do not render the overall composition to have a stinging effect upon application to the skin.
The high solids polymer is useful as a skin protectant paint and is compatible with a variety of useful adjuvants such as aloe vera in mineral oil, vitamin E, vitamin A, palmitate, triclosan, methyl salicylate, menthol, capsicum oleoresin, tea tree oil, squalane, peppermint, citronella, spearmint, jojoba oil, sweet almond oil, other oil and oil soluble materials. Using oils with higher carbon chains will vary the evaporation rates and/or skin absorption rates and provide short term plasticizing of the polymer, which in turn gives the polymer coating a glossy visible appearance until the solvent evaporates and/or absorbs.
The compositions of this invention may be applied to the skin, mucous membranes, etc. in liquid form by utilization of an applicator, such as a brush, rod, finger, sponge, cloth, dropper, etc; in spray or mist form; or any other usable technique for applying a liquid to a surface.
Surprisingly, compositions of the present invention may be formulated to provide excellent sprayable siloxane-polymer containing compositions. A sprayable composition may surprisingly be provided having a polymer content of as high as 6-10% by weight.
Medicants may be incorporated into the liquid or solid, dried film bandages for ready or continual release as the invention provides for an inert, longlasting, highly permeable film which can contain medicant or other active agents to be applied to the skin, mucous membranes and other body areas on which it is desired to release the active agent over an extended period of time. Examples of useful medicants are fungicides, pesticides, antimicrobial agents, antiviral agents, antitumor agents, blood pressure and heart regulators, and many more. Other types of active agents which may be desirable to incorporate include perfumes, plant growth regulators, DEET, plant insecticides, UV and IR absorbers, etc.
Compositions of the present invention provide a treatment benefit to the cells of the skin. Particularly, compositions to the present invention can have a beneficial affect for the treatment of dry or irritated skin. Compositions of the present invention that have high solid content are particularly advantageous because they can be more easily observed after placement on the skin. These compositions tend to be easier to coat in thicker layers, which are more visible. Films formed by the compositions of the present invention are highly substantive, flexible and non-tacky. They tend to provide enhanced benefit to dry skin because they decrease the water loss from the skin. Additionally, the films tend to fill in cracks, fissures, and other damaged surfaces of the skin.
Compositions of the present invention may optionally incorporate pigments, glitters, opalescent materials and or surface optical brighteners, which may be added to the composition or suspended in the polymer solvent mix. The material may be redispersed with the help of hand agitation or using a mixing ball in the dispensing container, as is common in fingernail polishes and make-up containers. The compositions of this invention could be used for applications other than medical body care. For instance, the coating could be used as a water repellent, yet H2O vapor permeable, film applied to sanitary napkins, diapers, or panties. With the incorporation of mildewcides, the coating could be used to cover grout in tiled surfaces. The present compositions are further useful as a sunscreen with the incorporation of UV absorbers. Still other uses include forming films for use in eliminating chapped lips, treating skin and internal body surfaces, and providing protection to skin and other surfaces which may be medicated prior to application.
The present invention also provides unique compositions to be used as a minor component of a larger cosmetic composition. More specifically, a method of formulating cosmetics is provided, comprising utilizing a composition of the formula:
a) 1-40% of siloxane-containing polymer;
b) 60-99% of an Alkane-Based Siloxy Polymer Reaction Solvent; and
c) 0-10% of adjuvants;
As an ingredient in a cosmetic formulation. This method provides a stable and cost-effective system for introducing siloxane-containing polymers in beneficial amounts into cosmetic formulations, wherein the polymer need be present as only a small fraction of the overall cosmetic formulation. Such formulations include cosmetics such as facial and body powders, hair spray, shampoo and conditioner products, lotions, creams, mascaras, eye liners, nail polish, body paints, and the like. Cosmetic compositions of the present invention may include nail polishes, scar hiding compositions, waterproof eyeliners, skin covering make-up base, and skin crack fillers and sealers. Cosmetic compositions may be provided in the form of compacted powders, lotions, creams, gels, sticks, and the like. Additional cosmetic compositions include treatment for the hair, including styling aids, creams, gels, lotions, sprays, and the like. Compositions of the present invention may additionally find advantageous use as lipsticks.
In another embodiment of the present invention, a stable water based non-flammable emulsion is provided of the skin protectant polymer. Surprisingly, this formulation yields equivalent skin protection to the solvent-based polymer composition, and additionally dries in a suitable time frame that is similar to the more volatile solvent based system. Advantageously, the gel may be massaged into the skin until nearly dry for additional therapeutic benefits. Additionally, such compositions may be easier to use with protective gloves that are adversely affected by solvent-based compositions.
Preferred gel compositions comprise (a) 1-15% siloxane-containing polymer, (b)10-25% Alkane-Based Siloxy Polymer Reaction Solvent, (c) 0-10% adjuvants, (d) 38-88.5% water, and (e) 0.5-2 emulsifier.
The emulsion gel may optionally contain therapeutic ingredients in both the solvent oil and water phases. Examples of such ingredients are as follows: